Solar Energy Collecting Device

ABSTRACT

A solar energy collecting device includes a spherical concentrator, a track, a sliding element, and at least one solar panel. The track is curved and has a center overlapping with that of the spherical concentrator. The sliding element is disposed on the track, and is controlled to move along the track according to the motion of the Sun during the course of a day. The solar panel is mounted on the sliding element to move along with the sliding element. The solar panel faces the spherical concentrator. Thus, the sunlight can be focused on the solar panel by the spherical concentrator throughout the day.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a solar energy collectingdevice that includes a solar panel moving according to the motion of theSun.

2. The Prior Arts

Conventional solar thermal collectors or photovoltaic modules use asolar panel to collect the energy from the Sun and use the solar energyto generate electricity. Because the Earth spins on its axis, the Sunrises in the east and sets in the west. Furthermore, the Earth's axis istilted to its orbital plane by an angle of 23.5 degrees and orbitingaround the Sun. Therefore, the angles of incidence between the incomingsunlight and the normal of the solar panel vary with time and seasons.In order to minimize the angle of incidence and maximize the energyconversion efficiency, a tracker is provided to detect the angles ofincoming sunlight and an actuator device is provided to rotate the solarpanel making the solar panel perpendicular to the ray of light. In orderto collect as much energy as possible, the size of the solar panel isusually very large. However, due to the bulky solar panel, it needs anactuator device that can drive a heavy load, which increases the cost ofthe whole system.

In order to reduce the size of the solar panel, some solar energycollecting devices are provided with concentrators (reflectors orlenses). Referring to FIG. 1, a solar energy collecting device has aconcave reflective mirror A to reflect and focus the sunlight onto asolar panel B. Because the light from a large-sized reflective mirror Ais concentrated onto the small-sized solar panel B, the manufacture costof the solar panel is reduced. However, the reflective mirror A is largeand needs to be rotated for facing the Sun directly. As a result, thesolar energy collecting device still needs an actuator device that candrive the heavy load of the mirror. Therefore, the solar energycollecting device is still expensive and consumes a lot of power.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide a solarenergy collecting device, which solves the aforementioned problems ofconventional designs that the cost of reflectors, lenses and actuatordevices are high.

Another objective of the present invention is to provide a solar energycollecting device having a small-size solar panel which can be selfadjusted according to the Earth's spinning about its own axis, therebykeeping the solar panel to be perpendicular to the ray of the Sun. Thus,the solar energy collecting device can receive optimal light irradiationas the angles of the incoming sunlight changes and does not need anexpensive actuator device for driving heavy lenses or mirrors.

In order to accomplish the objectives mentioned above, a solar energycollecting device according to the present invention comprises aspherical concentrator, a track, a sliding element and at least onesolar panel. The track is curved and concentric with the sphericalconcentrator. The sliding element is disposed on the track, and iscontrolled to move along the track according to the motion of the Sunduring the course of a day. The solar panel is disposed on the slidingelement and faces the spherical concentrator, such that the light isfocused on the solar panel by the spherical concentrator.

The track can be mounted on another track or device to adjust theorientation of the track according to the angles of the incomingsunlight due to the season variation. Thus, it ensures that the sunlightis constantly focused on the track after traveling through the sphericalconcentrator.

According to an embodiment, the spherical concentrator is a solid spheremade of a material that can focus sunlight, such as glass andpolyurethane.

According to another embodiment, the spherical concentrator is a hollowsphere made of glass or polyurethane and the interior of the sphericalconcentrator is filled with a liquid.

Because the concentrator is spherical, the focal point always falls on aline connecting the Sun and the center of the spherical concentrator,regardless of the motion of the Sun. The focal length depends on thediameter of the spherical concentrator, so the focal length is aconstant. Therefore, as the Sun moves across the sky during the courseof the day, the focal point would move along a circular path. The trackis overlapped with the circular path. As a result, the solar energycollecting device according to the present invention only needs tocontrol the small-sized solar panel to move along the circular pathaccording to the motion of the Sun and the sunlight would be focused onthe solar panel. Compared with conventional design, the presentinvention does not need to drive a heavy concentrator (lens orreflector), numerous concentrators or racks holding the concentrator andtherefore the actuator device is greatly simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art byreading the following detailed description of preferred embodimentsthereof, with reference to the attached drawings, in which:

FIG. 1 is a perspective view showing a conventional solar energycollecting device having a reflective mirror;

FIG. 2 is a schematic view showing a solar energy collecting deviceaccording to a first embodiment of the present invention;

FIG. 3 is a schematic view showing the solar energy collecting device ofFIG. 2, wherein a solar panel mounted on a sliding element is movedalong a track according to the motion of the Sun;

FIG. 4 is a schematic view showing a solar energy collecting deviceaccording to a second embodiment of the present invention; and

FIG. 5 is a schematic view showing the solar energy collecting device ofFIG. 4, wherein a solar panel mounted on a sliding element is movedalong a track according to the motion of the Sun.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 2, a solar energy collecting device according to afirst embodiment of the present invention comprises a sphericalconcentrator 1, a track 2, a sliding element 3 and at least one solarpanel 4. According to the first embodiment, the spherical concentrator 1is a solid sphere made of a transparent material, such as glass,polyurethane (PU) and acrylic. The larger the diameter of the sphericalconcentrator 1 is, the larger area is provided to collect solar energy.Therefore, the diameter of the spherical concentrator 1 is selectedaccording to the desired solar collecting area of the sphericalconcentrator 1. The track 2 is curved and has a center overlapping withthat of the spherical concentrator 1. In other words, the track 2 is apart of a circle which has a predetermined radius and is concentric withthe spherical concentrator 1. According to another embodiment, the track2 may also include a plurality of straight segments forming the part ofthe circle. The solar panel 4 is fixed on the sliding element 3. Thesliding element 3 is a carrier element provided with a driving device,such as a motor. The sliding element 3 may include wheels allowing thesliding element 3 to move along the track 2. The sliding element 3 ispre-programmed to move according to the motion of the Sun through theday. According to another embodiment, a conventional solar trackingdevice may be used to track the motion of the Sun in the sky and sendsignals to control movements of the sliding element 3, such that thelight is focused by the spherical concentrator 1 on the surface of thesolar panel 4 mounted on the sliding device 3.

When the Earth revolves around the Sun, the axis of the Earth is tilted23.5 degrees from the perpendicular to the Earth-Sun plane. Because theaxial tilt of the Earth, the angle of sunlight reaching any given pointon the surface of the Earth varies over the course of the year (thenorthern hemisphere is exposed to direct sunlight in summer, and thesouthern hemisphere is exposed to direct sunlight in winter). In orderto collect direct sunlight irradiation throughout the year, the track 2can be mounted on another track or device (not shown in the drawings).Therefore, the orientation of the track 2 can be adjusted responding tothe solar direction due to the season variation, which ensures thespherical concentrator 1 always concentrates the incoming light onto thesolar panel 4.

The spherical concentrator 1 of the solar energy collecting deviceaccording to the first embodiment of the present invention is ratherbulky and heavy, so the spherical concentrator 1 is held stationary. Assunlight emitted from the Sun 5 travels through the sphericalconcentrator 1, it is refracted and focused to converge on the solarpanel 4. Referring to FIG. 3, when the Sun moves, the sliding element 3is driven to move along the track 2 at a suitable speed to allow theconverged light to always fall on the solar panel 4.

Referring to FIG. 4, a solar energy collecting device according to asecond embodiment of the present invention comprises a hollow sphericalconcentrator 1A, a track 2, a sliding element 3 and at least one solarpanel 4. The spherical concentrator 1A is a hollow sphere having anexterior shell and an interior space. The exterior shell of thespherical concentrator 1A is made of glass, polyurethane (PU), acrylicor similar transparent materials. The interior space of the hollowspherical concentrator 1A is filled with liquid 11, such as water. Theliquid 11 may be another material having good transmittance of light.The diameter of the spherical concentrator 1 is selected according tothe desired solar energy collecting area of the spherical concentrator1. The track 2 is curved and has a center overlapping with that of thespherical concentrator 1. In other words, the track 2 is a part of acircle which has a predetermined radius and is concentric with thespherical concentrator 1A. According to another embodiment, the track 2may also include a plurality of straight segments forming the part ofthe circle. The solar panel 4 is fixed on the sliding element 3. Thesame as the first embodiment, the sliding element 3 is a carrier elementprovided with a driving device. The sliding element 3 may include wheelsallowing the sliding element 3 to move along the track 2. The slidingelement 3 is programmed to move according to the motion of the Sunthrough the day. Alternatively, a conventional solar tracking device maybe used to track the motion of the Sun in the sky and control movementsof the sliding element 3, such that the incoming light is focused by thespherical concentrator 1A on the surface of the solar panel 4 disposedon the sliding device 3.

Referring to FIG. 5, as sunlight emitted from the Sun 5 travels throughthe spherical concentrator 1A and the liquid 11 according to the secondembodiment of the present invention, it is refracted and focused toconverge on the solar panel 4. When the Sun moves across the sky, thesliding element 3 is driven to move along the track 2 at a suitablespeed to allow the converged light to always fall on the solar panel 4.

Although the present invention has been described with reference to thepreferred embodiments thereof, it is apparent to those skilled in theart that a variety of modifications and changes may be made withoutdeparting from the scope of the present invention which is intended tobe defined by the appended claims.

1. A solar energy collecting device, comprising: a spherical concentrator; a track being curved and concentric with the spherical concentrator; a sliding element disposed on the track and driven to move along the track in accordance with a motion of the Sun; and at least one solar panel mounted on the sliding element and facing the spherical concentrator; wherein the solar panel is moved along with the sliding element such that the spherical concentrator focuses the light onto the solar panel.
 2. The device as claimed in claim 1, wherein the spherical concentrator is a solid sphere made of glass.
 3. The device as claimed in claim 1, wherein the spherical concentrator is a solid sphere made of polyurethane.
 4. The device as claimed in claim 1, wherein the spherical concentrator is a hollow sphere having an exterior shell and an interior space filled with a liquid.
 5. The device as claimed in claim 4, wherein the exterior shell of the hollow sphere is made of transparent polyurethane.
 6. The device as claimed in claim 4, wherein the exterior shell of the hollow sphere is made of transparent glass. 